


Trigonometry

by largoindminor



Category: Supernatural
Genre: Destiel - Freeform, M/M, dub con, evil!Sam, moc!dean, sastiel (sort of), wincest (unrequited)
Language: English
Status: Completed
Published: 2015-02-21
Updated: 2015-02-21
Packaged: 2018-03-14 00:56:33
Rating: Mature
Warnings: Major Character Death
Chapters: 1
Words: 775
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3402530
Author URL: https://archiveofourown.org/users/largoindminor/pseuds/largoindminor
Summary: <blockquote class="userstuff">
              <p>Sam's bitter, envious of Cas and Dean's relationship, and realizes an opportunity to eliminate the angel for good.</p>
            </blockquote>





	Trigonometry

**Author's Note:**

> posted earlier [ here ](http://sasquatchandleatherjacket.tumblr.com/post/111614843797/so-in-the-car-this-morning-i-thought-to-myself)
> 
> kind of dark again, just my head space lately, but i hope you enjoy it! (i tagged as dub con but idk if someone thinks it should be non con let me know?)

Sam sees them. Dean tries to hide it at first, Dean knows about Sam of course. Knows everything about Sam. So they’re discreet, he and Cas. Sam sees, though, the little touches that linger longer than they should. The eye contact, the shared joke, the non verbal communication. Sam sees and seethes. The angel, the outsider, the interloper, stealing Sam’s place at his brother’s side. Sam says nothing.

Sam sees his chance, finally, and feels a momentary pang of regret. Dean doesn’t deserve this, not really, but Sam wants, and needs. He knows he can never have what he wants, but if he can’t, no one else can have it either. So when Dean falters a bit, when Sam coaxes out of him the details of the fears Cain placed in Dean’s head, Sam knows it’s his one chance.

First, kill the demon. Should be simple enough to provoke. Sam makes a call, his false voice wavering, sobbing. “Dean. Help.” He stages an elaborate scene. He cuts himself, bloodies his own face, plants evidence, frames Crowley. And waits. Dean comes, of course he does, always will. Crowley goes down surprisingly easy, caught entirely unawares. Dean mourns after, not for the demon but for himself.

Cas won’t go as easily. Sam knows Dean won’t do it, not ever, on his own. He’ll need the blade, he’ll need to lose himself entirely. Sam is more determined than ever to find the cure. Dean is grateful. Cas is grateful. Sam tells Cas he needs the blade, needs it to find the answers. Cas doesn’t understand, but he helps, he’s desperate to save Dean, he takes Sam to where it’s hidden.

Sam knows exactly where to go next, knows who will have the answers, knows his bargaining chips. It’s mutually beneficial. Cas gone, that’s what they both want. Sam promises it will happen, promises Metatron release, the blade, heaven, whatever he wants. Anything but Dean. They strike the deal, Sam learns the cure.

Turning Dean against Cas is hard, but possible. Dean loves the angel, but he loves Sam too. He’ll chose Sam in the end, out of guilt or responsibility, but Sam doesn’t care why. He starts small, manufacturing small misunderstandings. Everyone’s on edge, irritable, it’s not hard to instigate arguments, to seed mistrust.

The final plan is rough, even for Sam, his conscience aches from it, but he pushes it down, there’ll be time for guilt later. It takes help from a witch, an illusion spell, a strong one, but Cas is convinced by it. Cas is convinced the lips he’s kissing are Dean’s, convinced it’s Dean’s body he’s worshiping. Sam endures it, kisses back, slips his pants down low and offers himself like he knows Dean does, bides the time until Dean walks in. Sam stops, pushes at Cas. Screams. “No! Dean, help. Help me.”

Dean believes his eyes, he sees his angel buried in his little brother, tears in his brother’s eyes. He doesn’t want to believe but he does. The blade is there, just to his right, odd but convenient. He reaches for it, lunges at Cas, slashes at him, slices right through. There’s a flash of light, smell of burning as the elaborate pattern of wings etches itself into the floor, and Cas is gone.

Sam acts fast, fastens his jeans back together as he reaches for the cure. Uses the borrowed grace, the blessed blood, says words the scribe taught him. Dean collapses, cries out in pain, gripping his arm. Stills. He’s confused, the cure wipes the mark, it wipes this memory as well. He sees Cas’s lifeless body, crawls over to it. Looks at the bloody blade still in his hand and tosses it away.

“I… Sam, did I…? Oh, oh god no.” Dean breaks. He sobs. Sobs _sorry_ and _love_ and _no_ into Cas’s naked chest.

Sam walks over, sinks to the ground next to Dean, places an arm lightly on his shoulder.

“You- you don’t remember? You, uh, attacked him, you found the blade and just, lost it I think. I came in just as you- just when it was over. I found it, the cure, I- Dean I was too late, I’m so sorry.” Sam’s proud of himself, he sounds sincere.

Dean looks at Sam, slumps onto him and shivers with grief. Sam almost feels bad, almost, but Dean’s body pressed up against his feels too good for him to care. He soothes Dean, rubs circles on his back. Shushes his sobs. Sam looks away when Dean reaches for Cas, when Dean places a soft kiss on the angel’s lifeless lips. _It’s the last time_ Sam thinks, giddy.


End file.
